Vitamin D Supplements To The Elderly

Published Date: 02 Nov 2017

Introduction

Vitamin D is fat-soluble vitamins obtain by humans through the intake of diet and sunlight exposure. There are few natural foods that humans can obtain vitamin D out of them. Such foods are the fatty fishes, meat, eggs and cod liver oil, whilst some foods like milk, margarines orange juice and some flour products are also fortified with vitamin D in some countries. Human’s exposure to sun light stimulates cutaneous synthesis of vitamin D by ultraviolet radiation (Whiting and Calvo 2006; Chen et al. 2007)

Vitamin D has the importance of keeping the bones strong and dense; it also help the body in the maintaining the levels of calcium and phosphorous in the blood and aids the absorption of these element in the intestines; it may boost the body’s immune system by increasing the body’s T cells response capacity to fight against infections and certain forms of cancers. The absorption of intestinal calcium and the stimulation of re-absorption of bone are the primary role of the vitamin D but its role is not limited to the metabolism of calcium and phosphate ant its regulation in which the bone has been known to be the main targeted organ, but recent evidence has shown that it has anti-inflammatory and anti-proliferative properties and, the nervous system and the muscles are also target organs of vitamin D (Reid et al. 2003; Norman et al. 2007; Melamed et al. 2008)

There are many researches targeting the benefit of supplementation of vitamin D to reduce such deficiency to improve health and to sustain life. It is always critical to evaluate the effectiveness of such trials and their outcome measures so that effective policy and guidelines can be synthesized and be implemented.

Aim

The main aim of this review is to describe problems associated with vitamin D deficiency and its effect in the elderly people, with much focus on its definition, prevalence, and its effect as supplement to the elderly with particular attention to strength and stability of the bone and muscle to reduce fall and fracture.

Methodology

The risks of vitamin D deficiencies that this review describes are those that affect only the elderly. The review puts particular emphasis on studies that aim to test the importance of vitamin-D to the bone and the muscle in the elderly (both men and women). The review excluded other vitamin D deficiency risks that are not specific to the elderly. The author searched research articles from the Google website which lead the author to other journals such as PubMed, JAMA, J Am Geriatr Soc, J Intern Med, N Engl J Med. The author followed other publish articles to get the primary source of the main studies. The search identifies both observational studies and clinical trials but much emphasis was on the clinical trials.

Epidemiology of Vitamin D deficiency

The deficiency of vitamin-D is caused by any substance that has diminishing impact of solar UVB radiation to the earth surface, that interferes with UVB radiation penetration into the skin will influence cutaneous vitamin D3 synthesis or, taking diet which has low Vitamin D precursor. When people’s dietary intake does not contain the appropriate precursors of vitamin D or their exposure to sunlight is limited, vitamin D deficiency occurs which may lead to impairment and triggers the development of diseases.

There are factors that affect the synthesis of Vitamin D or contribute to its inadequacy. Melanin which is extremely efficient in UVB radiation absorbing for skin pigmentation affects or reduces markedly the synthesis of Vitamin D3 (Holick 2003; Chen et al. 2007). Sunscreen with 15 sun protection can absorb 99% of UVB radiation incident, thus it can decrease the skin’s vitamin D3 synthesis by 99%. People with very dark skin are hard hit by about 99% reduction in the synthesis of vitamin D because they have SPF of 15. They may need about three to five times sun exposure as a white skin person to synthesis similar quantity of vitamin-D. The nature of vitamin D as fat soluble makes it easily absorbed by the adipose tissue which makes obesity as one factor associated with vitamin deficiency (Clemens et al. 1982; Matsuoka1987; Wortsman et al. 2000; Chen et al. 2007; Hintzpeter et al. 2008).

There is an estimated 50% to 60% deficiency in vitamin D existing in the older population in North America and across the world (Bischoff-Ferrari et al. 2006; Autier and Gandini 2007; Norman et al. 2007; Melamed et al. 2008; Zittermann et al.. 2009). Available data also suggest an estimation of about I billion people worldwide have either vitamin D deficiency or insufficiency. Several studies on elderly men and women in the communities (excluding those in nursing homes) in the US and the European Union have reported 40 to 100 percent vitamin D deficiency. Research has shown that about 50 % of post-menopausal who are on osteoporosis medications had sub optimal 25-hydroxyvitamin levels below 30ng/ ml (Holick 2005; Holick et al. 2005; Lips et al. 2006)

The deficiency of vitamin D has been linked to most-cause mortality, cardiovascular disease and cancers - including breast, colon, and ovarian cancers and, supplementation of Vitamin-D is linked with significant in mortality reduction (Peterlik and Cross 2005; Melamed 2008). Universally, the accepted concentration level of 25-OHD is taken as the indicator for measuring vitamin D status because it is easy to measure, it can last from 2 to 3 weeks in circulation (Adams et al. 1982; Reichel et al. 1989; Wolpowitz and Gilchrest 2006). The deficiency of vitamin D, as agreed by experts, is said to be less than 20 ng/dL 25(OH) D and insufficiency is between 21 to 29 ng /dl 25(OH) D. Vitamin D level above 30 ng /dl or greater is deemed sufficient (Dawson-Hughes 2005).

The consequences of vitamin D deficiency in elderly people

There is the decreased presence of 7-dehydrocholestorol in elderly peoples skin, a precursor which mediates the synthesis of vitamin D, and the lack of exposure to the sun due to reduced mobility and institutionalizations, which makes them always at risk of vitamin D deficiency (Need 1993; Bell 1995). This phenomenon affects most elderly people in the western and other countries who have less sunshine, long winter times and the above situations than those they live in warm climate areas. The reduction of the 7-dehydrocholesterol in the skin of the elderly means less vitamin D production hence deficiency. Howbeit, there are many evidence that supplementation can be used to replace the lost.

The Deficiency of Vitamin D and the Bone

The elderly face the consequences of vitamin D deficiency on bone health. This includes osteoporosis and the increase risk for fractures. This fracture seriously affects or impacts the quality of life and survival in the elderly, especially the hip bone, forearm and the vertebrae (Bischoff-Ferrari et al. 2006; Snijder et al. 2006; Holick 2007). A person’s old age bone mass is the peak bone mass function achieved in their mid-twenties and, the ensuing rates of bone loss. In women bone mass loss becomes hastier during menopause and continues after that period as the efficiency of calcium absorption continues to decline and the Parathyroid hormones and, bone re-absorption rises subsequently. In men the loss of bone mass is at steady after the age of 50 years (Gallagher et al.2000).

Vitamin D and the Muscle

The interaction of vitamin D and the muscles is well documented but there are few and old clinical trials on the benefit of vitamin D supplement on the Muscle. There should be an appreciation of vitamin D deficiency effect on the muscles that makes it weak and increase the risk of swaying and falling that leads to the increase risk of these fractures in the frail elderly. On average men lose about 1.6kg of lean tissue and 0.6kg in women each decade. There are vitamin D receptors on muscles that bind to it and lead to its increase in strength and stability. The loss of muscle mass results in decrease in the receptors and muscle strength which leads to an increase in risk of falling (Gallagher et al.. 2000; Bischoff-Ferrari et al. 2006; Snijder et al. 2006; Holick 2007).

The benefit of giving Vitamin D Supplement to the elderly

As discussed earlier vitamin D deficiency has it heavy tolls on the elderly and that it is hypothesized that it supplementation would alleviate its myriad effect on them, but at

What concentration of Vitamin D would be beneficial to the elderly?

Can vitamin D supplementation alone achieve the required results or be coupled with other nutrients to achieve the target?

Vitamin D Effects on the Bone, Muscles, Fall, Fracture and Physical Performance

There is estimation that a daily provision of at least 800 IU of vitamin D can reduce the falling risk in the elderly as much as 72 % and a fracture by more than 50 percent. These claims needs to be reviewed to ascertain reality with consideration of research methodologies and the outcome measures analysis (Broe et al. 2007; Bischoff-Ferrari et al. 2009).

Bischoff-Ferrari et al. (2006) showed that a daily supplementation of 700units of Vitamin-D and 500 mg/calcium combination in addition to diet obtained by less active elderly women reduced falls by as much as 65 %. But this has neutral effect on men.

Flicker et al. (2005) showed a reduction risk of falls in the treatment group (0.73; 95 % confidence interval: 0.57, 0.95), when they randomly assigned 625 individuals with the mean age of 83 years in an assisted living facility. Those with insufficient 25-OHD concentrations received treatment with 30 ug (1200 IU) daily dose of vitamin D2 or daily placebo intake. The outcome suggests a dose effect because those they took at least half of the supplement had the greater effect. This is supported by Broe et al. (2007) as discussed below.

Broe et al. (2007) showed a remarkable result on the effect of higher dose of vitamin D in the reduction of falls in a randomized control trial. They recorded a 44% fall in the placebo group, 58 % in the 25-OHD concentration of 200IU group, 60 % in the 25-OHD concentration 400 IU, 60 % in the 25-OHD concentration of 600IU and 20% in the 25-OHD concentration 800 IU with (5/23). Individuals with the 25-OHD concentration 800 IU group had a 72% lower adjusted-incidence rate ratio of falls than those in the placebo group over month 5 (RR=0.28; 95% CI=0.11-0.75). This conclude that the higher the dose the lower the risk of fall because those individuals in the 800 IU recorded the lowest number of fallers and a lowest incidence rate of falls over month 5. But there is problem with sample size because there were fewer subject in the study, 26 in the study group.

Bischoff-Ferrari et al. (2010) showed a contradicting result of provision of high dose of vitamin D to elderly in the reduction of fall, although, fall was the primary outcome measure. Participants at baseline had 12ng/mol others less than 30ng/ml. The study recorded no reduction of falls from the 25-OHD 2000 vs 800 IU/d 28%; 95% CI,-4% - 68 %.

The inconsistences in the outcomes make it difficult to come into conclusion of the actual benefits of vitamin D supplementation and the dose to prevent falls in the elderly.

Bischoff-Ferrari et al. (2005) conducted meta-analysis based on 12 trials on the benefits of vitamin D supplement to the elderly above 60 years with a total 19.114 women living at homes. They reported a significant relative risk reduction of hip fracture by 26% and 23% for other non-vertebral fractures.

Wicherts et al. (2007) on vitamin status and physical performance and its decline in older person, observed that 25-OHD serum was associated with physical performance because individuals with 25-OHD serum less than 10 ng/ml, were poorer in terms of physical performance as compared to those individuals with 25-HD levels above 30 ng/ ml ( (B) = -1.69; (CI) = -2.28; - 1.10). After confounding variables adjustments these individuals had a higher odds ratio for a 3-year degeneration in performance (ODDS RATION = 2.21; 95% CONFIDENCE INTERVAL = 1.00-4.87; and ODDS RATION 2.01; 95% CONFIDENCE INTERVAL =1.06 – 3.81) when we compare it with those individuals above 30 ng/ml. This study shows that an increase in 25-OHD serum concentration has an association with physical performance which most elderly people are not interested.

Zhu et al. (2010) showed that vitamin D has beneficial effect on muscle strength and mobility. They recorded an increase in baseline serum 25-OHD from, mean ± standard deviation 17.7 ± 4.2 ng/mL, to mean ± standard deviation 24.0 ± 5.6 ng/mL in the treatment group after one year. There was no increase in the placebo group. The study showed an improvement in muscle strength and TUAG by vitamin in those with lowest concentration more than calcium alone in Hip Extensors (HE) and Hip Adductors (HA) [mean (standard error): HE 22.6%; HA 13.5 %; TUAG 17.5 % (7.6), P < 0.05] . This study showed the benefit of vitamin D to increase muscle strength and stability even in those who were weakest and slowest at baseline.

There are mixed results in randomized control trials on the effect of vitamin D supplement on muscle strength. Stockton et al. (2011) had no significant effect of vitamin D on lower extremities muscle strength from their meta-analysis, with the exception of individuals with serum 25-OHD starting point at levels < 25nmol/l. Although this possibility remain, the major role of vitamin D in the improvement of muscle strength and mass of elders with serum concentration of 25-OHD levels in the range of 25-75 nmol/l are not strongly supported by these studies.

Conclusion

Most researches never reported on compliance of elderly people in the situation of physical activities which also promotes the development of bones and muscles strength. Crombie et al. (2007) showed that the main reason that has been a limitation for the elderly people in the participation in physical activities was their lack of interest in physical activities. This will affect most interventions that are targeted at fall prevention to achieve its optimum results. Most of the studies found were skewed towards female subjects and that will affect its generalizability as Bischoff-Ferrari et al. (2006) had neutral effect in men when in women there was 65% reduction in falls.

Trials should take baseline 25-OHD concentration of individuals before randomization so that good evaluation and analysis can be made. Age sex, location and other details should be considered in future trials to control confounding.

There are mixed results from the studies reviewed on the benefit of vitamin D to the elderly. The IOM recommends that meta-analysis on the benefit be stopped because of the discrepancies in the study design and analysis. Some studies that did not meet inclusion criteria were added to some studies. And studies combined calcium with calcium before achieving such results which means vitamin D alone is insufficient.

The hypothesis of the benefit of vitamin D to the elderly in strengthening bone mass, improve muscle strength and stability which will then help reduce falls and leads to fracture reduction is backed by research, but the mechanism that will make elderly achieve the maximum benefit is still not understood by the scientific community. The author recommends that there should be more observation studies to generate additional hypothesis to direct future clinical trials to achieve this mechanism.